1. Field of the Invention
The present invention pertains to seismic data processing, and, more particularly, to a method and apparatus for using a set of seismic data contemporaneously across multiple seismic domains.
2. Description of the Related Art
Seismic prospecting generally involves generating one or more sets of seismic data regarding a subterranean geological formation. A variety of techniques analyze seismic data with the goal of identifying characteristics of the geological formation that may indicate the presence of hydrocarbon deposits. Some techniques are directed to improving the quality of the seismic data. “Stacking,” for instance, is a process in which traces (i.e., seismic data recorded from a single channel of a seismic survey) are added together from different records to reduce noise and improve overall data quality. Characteristics of seismic data (e.g., time, frequency, depth) derived from stacked data are referred to as “post-stack” but are referred to as “pre-stack” if derived from unstacked data. Other techniques, however, pertain more directly to the substantive analysis of the seismic data.
Such techniques commonly apply a velocity model to the seismic data. The velocity model is used by dynamic conversion mechanisms that converts the seismic data from one seismic domain into other seismic data in another seismic domain. (e.g., stacking, pre or post-stack, time or depth migration). For instance, the seismic data may be presented in a time, or a depth domain, a pre or post stack domain, a migrated or un-migrated domain, an acoustic or elastic domain, a specific historic time domain (for 4D data) etc. Some commonly used seismic domains include:                pre-stack time (raw or migrated);        pre-stack time (acoustic or elastic, including converted);        post-stack time (migrated or un-migrated);        post-stack depth (migrated pre or post-stack, re-migrated);        pre-stack depth;        depth;        pre-stack acoustic (“PP”);        pre-stack converted (“PS”); and        four-dimensional (“4D”) seismic data from different vintages;This list is not exhaustive, however, as the art employs still other seismic domains.        
It is well known that each seismic domain is limited in its capabilities to completely image the subsurface. For instance, in the unmigrated seismic domain, events are distorted and interfere with each other, while in the migrated domain, events have a much more geological aspect, but there are migration artifacts. In the time domain, events are mispositioned laterally, while in the depth domain, they should be closer to true geological position, depending on the Earth velocity model correctness. However some migration algorithms lose information recorded in the time domain (e.g., steep flanks, multiple arrivals, etc). PP data cannot image through gas clouds while converted PS data can, etc.
However, different seismic domains can carry complementary information, and therefore should be considered in concert. Those in the art commonly consider the seismic data in one or more domains through concurrent (i.e., roughly at the same time) visualizations of the data in multiple seismic domains. Typically, such a visualization is a graphical display, and each display may be referred to as a “visualization canvas.”
Analysts find it useful to link visualizations of different seismic domains so that a data point under consideration in one seismic domain is graphically indicated in a second seismic domain. Well known methods exist which attempt to link different seismic domains in a graphic environment. Exemplary conventional methods include:                on-the-fly time-to-depth or depth-to-time conversion of the seismic display (e.g., for seismic synthetic generation based on well logs), time-to-depth conversion of the seismic interpretation (sometimes called “map migration”), etc.;        superposition of the interpretation coming from different seismic domains on the same seismic domain display (e.g., PS depth interpretation in the PP depth seismic domain display or vice versa; representing several vintages of 4D seismic interpretation on the same seismic vintage display);        cursor tracking between two or several two-dimensional (“2D”) frames of similar seismic domains (e.g., either all in time or all in depth) based on their geographical location (e.g., cursor tracking between a PP time seismic version and a PS time seismic version); and        ray path display to link the geographical location of the source, receiver, and reflection point, but not the travel time and the reflection point.However, these methods have some problems.        
Although very useful to get a rough insight of the link between different seismic domains, these methods are sometimes based on simplistic assumptions regarding the conversion between the domains (e.g., vertical stretch and vertical assumptions for velocity extraction) and, moreover, are not consistent with the dynamic conversion applied to the seismic data (e.g., vertical stretch is used between post-stack time migrated domain and post-stack depth migrated domain). Therefore, they are erroneous and can be misleading as soon as the simplistic assumptions are not fulfilled (e.g., dipping structures, faults, lateral velocity variations, anisotropy, etc.).
The present invention is directed to resolving, or at least reducing, one or all of the problems mentioned above.